It is time to tilt at the windmills again. Nearly four years after a wildly optimistic speech in Prague—in which he outlined his dream of a nuclear weapons-free world—US President Barack Obama is again, trying to revive big-ticket nuclear disarmament.

Details of the plan are sketchy—The New York Times reported on the move on Monday—but part of the deal is expected to be “informal”. While no specific cuts or numbers have been proposed, the report suggested a number “just above” 1,000 nuclear warheads. The deal is expected to be “informal” as a formal agreement will lead to the Russians demanding a scaling back of missile defence in Europe. This will lead to intense political bloodletting in the US senate, something Obama does not have the numbers or the stamina for.

As always, such efforts are sound in intent but fiendishly hard to implement. In the end everything boils down to two issues: commitment and transparent implementation. But that may no longer be an issue in global disarmament. The danger comes from other sources.

For one, the danger is no longer of Armageddon between two Great Powers. The danger of a nuclear race—and ultimately a nuclear exchange—comes from “middling powers” such as Iran and Saudi Arabia that consider these weapons as being indispensable for securing geopolitical goals. For another, a deal between the US and Russia will only have a limited impact on global disarmament. Unless China is part of such a deal, the spread of weapons cannot be halted. Without China disarming, India will not even consider a move towards giving up nuclear weapons. Similarly, without an explicit Indian disavowal of these weapons, Pakistan won’t budge. Coordinating such large-scale change in the global nuclear regime requires much effort and preparation. In this case, there are no such signs.

If at all Obama is serious about disarmament, the US has to first make up its mind and agree to delinking nuclear weapons from operational doctrines. So long as these weapons continue to be part of US’s military strategy, the chances of Russia and China agreeing to aggressive weapons reduction will be close to non-existent.